Coupling actuated magnetic switch



Nov. 6, 1951 w. MCLEOD 2,573,920

COUPLING ACTUATED MAGNETIC SWITCH Filed April 25, 1949 2 SHEETSP-SHEET 1If)!!! If INVENTOR.

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Patented Nov. 6, 1951 UNITED STATES PATENT OFFICE 2,573,920 COUPLINGACTUATED MAGNETIC SWITCH William McLeod, Chicago, 111. Application April25, 1949, Serial No. 89,386

This invention relates to improvements in electrical connectors,switches, fixtures, and like devices or units. Generally speaking theinvention herein disclosed has to do with such devices as sockets andplugs intended for use as outlets for so-called base-boards and likeinstallations, and for other similar installations wherein an extensioncircuit is to be established; but it will also appear that my presentimprovements are also well adapted for use in many other locations, andfor many other purposes. For example these improvements are well adaptedfor use in connection with lamp sockets and bases intended forintroduction into such sockets; and for use in switches and like circuitcontrolling units. Some of these applications of the present inventionwill be illustrated and described hereinafter.

One object of the invention is to provide a socket element and plug foruse in connection therewith, both of such form that when the plug is notin place in the socket the electrical terminals of such socket will bedead or nonelectrified, and such that when the plug is set into place inor in connection with such socket the terminals of the socket willimmediately become electrified so as to establish and complete theelectrical circuit between the socket and the plug. By this means theterminals of the socket will be at all times electrically dead when suchterminals are exposed due to the absence of the complementary plug. Thusdanger of improper connection to such socket terminals will becompletely avoided, and resulting short-circuiting will be prevented. Inlike manner, danger of shocks occasioned by contact with the exposedsocket terminals will be prevented. Many other advantages resulting fromthis arrangement will manifest themselves from a study of the presentdisclosures.

It is a further object of the invention to enclose the connections tothe socket terminals within a sealed container or compartment havingonly sealed and non-moving connections to the outside of suchcompartment, so that perfoot sealing of the compartment may beelffected, and so that the perfectl sealed condition of this compartmentwill be maintained for an indefinitely long interval and after a greatnumber of attaching and detaching operations of the complementary plugwith the socket. By this means, also, said connections within saidcompartment may be perfectly sealed against entrance of water, dirt, andother foreign matter, thus ensuring perfect and, con- 2 Claims. (Cl.200-51.09)

tinuous protection of said connections from the eflects of such water,dirt, and other foreign matter.

In addition to the use of my present improvements in connection withsockets and plugs therefor, there are many other applications whereinsaid improvements are or will be of great value. One specificapplication of said improvements relates to their use in connection withlamps and the sockets therefor.

When the features of my present invention are embodied in switchingunits, as such, the actual circuit closing and opening operations may beproduced completely within the housing or enclosure, or through elementswhich reach to the outside thereof. Both of these forms are illustratedin the drawings to be presently described.

Other objects and uses of the invention will appear from a detaileddescription of the same, which consists in the features of constructionand combinations of parts hereinafter described and claimed.

In the drawings:

Figure 1 shows a longitudinal section through a typical form of socketunit and complementary plug member, embodying the features of my presentinvention, the plug member being separated from the socket unit adistance suflicient to non-influence the magnetically responsiveelements of the socket unit, and to thus bring the exposed contacts ofthe socket unit into dead condition, and the plug contacts beingdisengaged from the exposed contacts of the socket unit;

Figure 2 shows a section similar to that of Figure 1, but with the plugmember engaged with the socket unit to thus electrify the exposedcontacts of the socket unit, and to bring the contacts of the plugmember into engagement with the exposed contacts of the socket unit;

Figure 3 shows an end view of the plug member of Figures 1 and 2;

Figure 4 shows a cross-section taken on the lien 4-4 of Figures 1 and 3;

Figure 5 shows a face view of the socket unit plate, with the housingremoved therefrom to show the form of the magnetically responsiveelements, and the spring elements for normally moving the movablecontacts of the socket unit into open circuit position to thusde-electrify the exposed contacts of the socket unit;

Figure 6 shows a modified form of plug member in which the plug memberis intended to make engagement with the socket unit by a rotaryconnection with a socket unit of the type shown in Figure 7;

Figure 9 shows a longitudinal sectionthrough another form of socket andplug combinationin which the engagement of the plug withthe socket i isby a sliding action, this figure being a section taken on the lines 9-9of Figures 10 and ll looking in the directions pf the arrows;

Figure 10 shows an end view of the plug mem- -ber of thearrangement ofFigure 9;

.Figure :11 shows a face-view of the socket unit of the arrangement ofFigure 9; #Figure 12 showsa longitudinal section through still anotherform of socketand plug combination' in which engagement of the plug withthe socket is by a rocking movement, the plug member 'being shown indisengaged or open circuit condition; both the arrangements of Figures9, l0 and I1, and of Figure vl2, being in effect switch constructions;and

Figure 13 shows another form of embodiment :of -my-invention into aswitch construction in which the movable or permanent magnet ele- *mentcarries no-portion of the current being controlled, all circuits andcontacts'being fully en'- closed in the housing-oi the socket unit.

Referring first to the embodiment of the inven tio'n shown in -Figures'1 to 5, inclusive, I have therein shown my'invention as embodied in acon- '=str'uction including the socket unit and the plug member-designated in their entireties by the numerals and 2 1, respectively.The socket unit is shown as including the insulating plate 22 to' theback side of which there are secured i'the-spring'leaf conductors ziiamaze, respectively, by the rivets or screws 25 and :26. The free ormovable ends '21 and 28 of these'leaf spring conductors come intosubstantial alignment as well shown in Figure 5. These free or movableends carry the armatures or keepers 29 and 3B of :soft :magne'tic ironor magnetizable material which will respond readilyto induced flux fromanother source. Thesecured ends 3! and 32 of these spring leaf elementsreadily provide terminal connectors @to whichthe-opposite-poles of thesource of current are connectedfin well understood manner. Set screws 33and 34 are shown for effecting suchconnections.

The insulating plate :22 compri es one wall of a housing for the partsjust described; and'a suitable enclosure is provided in connection forthis wall. In the arrangement shown in Figures :1 .to15, inclusive :thiszplate 22 is provided with the integral backwardly extending flange 35and a :removable cover plate .BE'is secured in water :tight fashion tothe edge :of this flange to comsplete "the housing enclosure. Itwill benoted "that-terminal connections may be made to the connectors Stand :32without having to open the enclosure pr housing. I

In the plate .22 there are securely carriedthe zfourcrivet-ilike plugsor studs 31, 3,8, as and ie.

These are preferably made of magnetic iron of rsoitrcharacter, so thatthesestudsmay :bereadily these studs. On the contrary, in Figure 2 thearmatures have been drawn towards and into contact with these studs 31,38, 39 and ti said "studs having been magnetized by flux induced inthem. Thus said studs are normally nonelectrified or dead, since theyare normally not contacted by the armatures Z9 and 39, which armaturescomprise electrical connecting means attached to the spring leaves 23and 2%, respectively.

The plug member 2! includes the two permanent magnet elements All and4-2. These are shown as beingof horse-shoe form. and the legs of thesetwo horse-shoes align with the studs 31, 38, 39 and 48 when theplug'member is brought into circuit connecting condition, as shown inFigure 2. These permanent magnets may be of any suitable materiaLsuch asAlnico 5 or other permanently magnetizable material of high retentivecharacter. These two permanent magnets are carried within sockets 4'3and M of an insulatingplug element 55 and conveniently these horse-shoemagnets :are retained within such sockets'3 and d l by meansof the crossbars '45 and 46 comprising ajportion of such element 555*, which is madeof insulating'material such as a synthetic moulded product. Examinationof Figures 1 and 2 shows that these horse-shoe magnets are ratherloosely set into their respective sockets 43 and 94-, so thatsaid'magnets' may move slightly back and forth,'and side to side, andwith slight rocking movements while being still retainedwithin thesockets by the cross bars 45 and 46. These horseeshoe magnets areconnected by the short and flexible pig-tail connectors 4'1 and 48 withthe terminal'screws 49 and Elkto which the double wire extension cord 5!is-connected'in well understood-manner. The plug element 45 is readilyformed of synthetic insulating material by a moulding process or othermeans; and a removable cover plate 52 is secured on to this element'inconvenient manner as by means of thescrew 53.

As already stated the legs of the two horseshoe'nriagnets'are spaced toalign with the studs 38, 39 and d9 of the socket unit when the plugmember is to be brought into connection with said socket unit. This factis well shown in Figures 1 and 2. Astheplug member is moved close to thesocket unitwith the magnet legs aligned as just explained, there will beflux induced throughmagnetic circuits including the studs 37, 38,39 and$9, and through the armatures 28 and so, thus drawing these armaturestowards and into contact with the studs, the armature 28 engaging thestuds 31' and 38, and the armature 3F! engaging the studs 35 and Ml. Assoonas this condition occurs it is evident that said studs willbeelectrified or cease to be dead, the studs 31 and 33 being of oneelectrical polarity, and the. studs 39 and as being of oppositeelectrical polarity. 3

This movement of the armatures 29 and into contact with the studs willgenerally anticipate actual engagementof the magnet legs with the studs'31, 38, 3s :and 34B, sothat by the time said magnet legs come intoactual contact with the studs,'said studs have become electrified. Theslight freedom of movement of the magnets within the sockets 43 and 44wherein they are accommodated is such as to allow said magnet legs tocome into good and even contact with the exposed ends of the studswithout exercise of great care by the user, so that when insertion ofthe plug member into the socket unit has been completed good electricalcontacts will be produced between the studs and the magnet legs. Thusthe necessary connections are eifected through the socket unit and theplug member to place the conductors of the cord 5! into connection withthe current supply lines.

As soon as the plug member is withdrawn sufficiently from the socketunit to disengage the magnet legs from the studs 31, 38, 39 and 40 airgaps will be created between the magnet legs and said studs so thatgreat and sudden increase of reluctance of the magnetic circuits willoccur, and the spring forces of the spring leaves 23 and 2 3 will atonce swing the armatures 29 and 30 away from the studs, thus breakingthe electrical connections between said armatures and studs. This willde-electrify said studs, so that they will again become dead andharmless.

Evidently the magnetic attraction between the horse-shoe magnets and thestuds and armatures will produce a holding force tending to prevent theplug member from being disconnected from the socket unit. This holdingforce will be considerable. However, it is desirable to provide forfurther and greater holding force between these parts, and I have madeprovision for the same. Thus, in the form shown in Figures 1 to 5,inclusive I have provided the inwardly reaching socket or opening 54 inthe end of the plug element 45' the opposite walls of this opening beingprovided with the inwardly extending ribs 55 and 55. The socket unit isprovided with a companion spring catch element 51, carried by the plate22, so that as the plug member is set into engagement with the socketunit this catch element will enter the socket 54 and provide suffi cientholding force between the plug member and the socket unit to meet normalholding requirements, but will not prevent intentional withdrawal of theplug member from the socket unit.

It is noted that although the studs 31, 38, 39 and 4d are normally deador Lin-electrified, they become electrified prior to actual contact ofthe horse-shoe magnets with these studs, since normally the attractionexerted on the armatures 2S and 3!! will become sufficiently great todraw said armatures towards the plugs prior to actual engagement of themagnet legs with said plugs. Likewise. upon withdrawing the plug memberfrom the socket unit the initial break will normally occur between themagnet legs and the outer ends of the studs, since the magnetic fluxwill not begin to reduce until an airgap has actually been createdbetween the magnet legs and the outer or exposed ends of the studs.However. when these improvements are used in connection with.so-calledextension cords. said cords are usually connected to a currentconsuming or using implement which is provided with a switch whereby thecurrent is actually turned on and 01?. Therefore when so used thebreaking of connection between the magnet legs and the studs 31. 38. 39and ill does not of itself open the current since such current hasalready been discontinued use of such a switch as .iust referred to.It'is, however, emphasized that whenever the plug member is disconnectedfrom the socket unit these studs become de-electrified and dead, withthe benefits already referred to.

The movement of the plug of the arrangement shown in Figures 1 to 5inclusive, with respect to the socket unit is a direct forward Orbackward movement. In Figures 6 and 7 I have shown a modifiedarrangement in which the movement of the plug member with respect to thesocket unit is rotary. In this case the plug member 58 carries the twohorse-shoe magnets (permanent), 59 and 6B, and the socket unit isprovided with the two companion armatures 6i and 62 carried by thespring leaf elements 53 and 6c, the arrangement being thus similar tothat of Figures 1 to 5, inclusive. However, in the present case thesocket unit is provided with the circular flange 65 which is of diameterto receive the base portion 66 of the plug member. The plug memher isprovided with the oppositely located lugs 61 and 68 which are adapted toengage with the flange 65 of the socket unit. For this purpose theflange 65 is provided with the two arcuate undercut grooves 69 an It!within which the lugs 67 and 68 will be accommodated; and suitablenotched openings 1| and 12 are provided in the flange to permit the lugs6'! and 58 to pass during insertion or removal of the base portion ofthe plug member into or from the socket unit.

The lugs 61 and 68 are so located with respect to the notches II and 12,and with respect to the line along which the studs 31, 38, 39 and 40 arelocated that when the plug is originally inserted into the base elementthe magnet legs are not in alignment with said studs. Then, by rockingor turning the base or plug member through approximately 30 degrees ofturn the magnet legs are brought into engagement with the exposed facesof the studs for the purposes already explained in full detail. Thus thefinal positioning of the plug member with respect to the socket unit isby a rotating movement. This form of device also is such that as long asthis proper alignment exists between the magnet legs and the studs, theplug member is locked to the socket unit, by what may be called abayonet-coupling arrangement.

The two magnets of the arrangement of Figures 6 and 7 may be connectedto the two wires of a cord in the well understood manner. However, ifdesired this plug member of Figures 6 and 7 may carry the currentconsuming unit itself. Thus, in the case shown in Figures 6 and 7 and 8there is an incandescent lamp 73 carried by this plug member, theterminals 24 and E5 of the filament 16 being connected to these magnetsso that Such filament is supplied directly with the required current.

Evidently the lamp arrangement shown in Figures 6, 7 and 8, and thesocket unit thereof, may be used in connection with a circuit which isprovided with a suitable control switch for normally turning the currenton and old. However, by use of the socket unit embodying the features ofthe present invention it is evident that when the lamp element isremoved from the socket unit the studs 31, 38, 39 and 4B are dead, sothat all danger of short-circuiting or improper connection to theelectric supply lines is eliminated.

The alignment of the magnet legs of the ar 7 rangement of Figures 6, 7and 8 with the studs of the socket unit is by sliding movement, althoughsuch sliding is rotary in direction. In Figures 9,1 0 and 11 I haveshown another modified'form-of construction in which the sliding antennamovement.- betweem the plug; member: and, the? socketunit rectilinear;Inzthis; casethe; socket; unit includes the studs.31z, 38=, 39 and.43:asbefore,, and. also includes the two armatures- 1i is carried by thespringleaves I9 and 8,0 inmanner similar to that of: the: previouslydescribed ar rangements. In the presentcase the plug mem-- ber includesa moulded unit 31 wherein the two: horse-shoe magnets 82 and 83- arecarried similar to previously described" arrangements: In: the presentcase the socket. unit is provided with a straight-line opening-84'somewhat longer than the'plug member unit 81, so; as to permitendw-isemovement of the plug member with respect tothe socket unit- The plugmember'is provided with laterally extending lugs 85 and 86 which: maybeset down through notches- B l and B8: of the socket unit to bring theface of theplugmember intocontact with or close? to the. surface of thesocket unit. The socket unit" is alsoprovided with undercut grooves 89arrdtilto accommodate these lugs for a sufiicient amount of. endwisemovement ofthe plug to'bring the mag-- netlegs into alignment withthestudslil, 38 39 and lil, for the purposeswhich have'already beenexplained.

Inthe arrangement shown in 'Figu-re-12 the plug member 9.! is. carriedby a pivoted connection 92* to the socket-unit 93, said socketunit-beingipro vided with the studs. 31,38,329 and 4i!- and. the plugmember 9!. beingprovided with the magnets 94; and 95. The socket unitis. provided with. the: armatures. $6v and Q'Lcarried by the springleaves 98.. and 99,.in. manner similar to. the arrangementshereinbefore. disclosed.v I

It is noted that in thearrangements of Fig ures 6, '7 and 8',and-Figures 9, lean-d 11, and Figure 12,. the magnet elements areaccommodated. within sockets fthe plug: membersof size to. allow somemovement of such magnet ole-- ments to enable them to come into goodcontact with the studs. 31,. 38-, 39 and 451, as will be readilyunderstood. a

Each of the plugs- 8t or 9tof. the arrange'- ments of Figures 9; 10. and11, or of- Figure. 12', may be provided with wire connections to the;wires of extension cords in well understood-.man ner. Howevenin. Figures9- and 10 I have; shown cross connections 1.9.0. joining the. twomagnets- 82. and 83 directlytogether, and in Figure 12 I have shown thecross. connection [ll-I. joining. the two magnets. 9.4 and 95 directlytogether; When these cross connecting wires areprovided: these plugs andtheir. companionsocket units may be usedas switches for controlling.circuits in well understood. manner.

I have already pointed out that" such :ar-- rangements as that ofFigures 1, 2, 3-, 4 and 5-the actualbreaking of. circuit, when no: othercircuit breaking means is provided, takesplacebetween the magnet legsand the exposed; faces of the. studs 3?, 38, 39 and 49 This would. alsobe. true; of the arrangements of. Figures 9,.10and L1,, and. Figure 12.When-such devices are to be used. as.

switches, such. action will occur; but generally such deviceswill be.used-in connection. with. circuits which arev provided with otherandspecial.

switch means I In Figure 131 have: shown still: another modifledarrangement in which thefactual. circuit making and breaking operations.are effected by, means other than theengagement otthe. magnet. legswiththe. studs31, 38, 39 and 40. .Inthecase of Figure 1.3 the socketunitI02 isprovidcdwith two studs Hi3 and l 04 reaching. through the-..wall-.

8. I; ofithe socket unit; and: saidwall also carries the two additionalcontacts 10% and H11 whiclr are insulated. from each other andconstitute-the: two terminalsof the'circuit to be switched. This;arrangement alsoincludes thearmature IOBcarried by the spring leaf H39;and this armature? also; carries the two movable contacts H0 and I l Iconnected by the wire 11 l and which are in-- sulated from thearmatureas shown in the figure.

: In. the case of Figure I3 I have provided themagnet H2 which ismovable towards and from the socket unit; and the legs'of this magnetmoveinto alignment with the studs I03 and I04 so: that. when the magnetis close to the socket-unit;

.; the studs are magnetized and the armature. is.

drawn towards the magnet, that towards. the wall I05 of the socket unit.As this occurs the: armature; carried contacts engage the stationarycontacts toclose the circuit; and vice versa, as

= the magnet-is moved away from the socket unit the armature isreleased, and is withdrawn by the leaf spring, to thus open the circuit.The socket unit of this arrangement may be provided" with a housing H3which provides, in connec-- tion. with the. wall Hi5, a water tightenclosurefor the movable parts andfor the contacts, both stationary andmovable If desired the enclosure. N3. of Figure 13 may be filled withoil or other suitable electrically insulating liquid to thus provide anoil-switch arrangement by use of. the construction of that figure.

In Figures 1 and 2' I have shown the springs: l M and H5 located behindthe magnet elements; 41 and 42, respectively, saidsprings being in the;form of leaf springs anchored to the plug body 2!, and having their freeends pressing against said magnets. These springs therefore exert-a.slight pressure tending to move the magnets towardsthe studs 31, 38, 39and 40 when the plugv member is engaged with the socket unit, so as; toensure good contact-between the magnets and: the studs. It is noted thatthe pig-tails 41 and. 48 have a slight stiffness tending to retain themagnets back away from the crossmembers 45 and 46 but in case suchstifiness should befound. excessive, tending to prevent goodengagement-oi, the. magnets with the studs. when. the plug member isvbrought into engagement with the. socket. unit,.these springs H4. andH5. may be-made of sufiicientstrength to ensure good. engagement'of themagnets with the studs to give good. electricalcontact betweentheseparts.

It. is notedthat in. each. of the embodiments; hereinillustra-ted themagnetsareshown as being.v carried by themovableelement,,previouslydesignated as the plug and. the. armatures. corresponding-to thesemagnets are. shown. as being. carried by the. stationary element,previously designated. as the. socket. It. will be evident,v

: however, that this, arrangement might. be. re.-

versed thev magnets. being. carried by the sta.-, tionary element, and.the armatures being carried. by the movable element.

It willbe noted that in the embodiment. shown in Figure 13 there are.shownonly two stationary. contacts, we. and I01, and two corresponding.contacts Ill), and HI carried, by the armature. "18.. However, the.number of such. contacts. may be either greater or smaller than shown,as. for example,,three or four, or more stationarycontacts, and acorresponding. number of, movable contacts. 7 a

It is. also noted that each of. the embodiments herein. illustratedprovisionhas been made.

5. fortwo. conductors which are controlled for Gilli-r.

cult opening and closing purposes. It will be evident, however, thateach of these embodiments might be provided with either contacts for asingle conductor, or for more than two conductors, for example, three,as in the case of making provision for a three phase circuit, or for athree wire system of distribution;

While I have herein shown and described only certain embodiments of thefeatures of my present invention, still I do not intend to limit myselfthereto, except as I may do so in the claims to follow.

I claim:

1. A detachable electric fixture comprising in combination a socketelement and a companion plug element, said socket element including apartition of insulating material, two pairs of studs of magnetizablematerial extending through said partition, two leaf springscorresponding to said pairs of studs and located at one side of saidpartition and having their anchored ends secured to the partition andtheir free ends in proximity to the corresponding pairs of studs andnormally retracted from said studs by the bias of said leaf springs andmovable towards said studs against such spring bias, a magnetizablearmature carried by the free end of each leaf spring in position forenergization by magnetic flux flowing through the corresponding pair ofstuds to thereby draw said armature into engagement with said studs whensaid studs are magnetically energized to thereby electrically contactsaid armature with said studs at such time, and electrical terminals inconnection With said leaf springs, and said plug element comprising ahousing, a pair of permanent U-shaped magnets individually movablymounted within said housing and electrically insulated from each otherand said magnets being spaced apart to correspond to the spacing apartof the pairs of studs, and the poles of each magnet being spaced tocorrespond to the spacing of the studs of the corresponding pair ofstuds, the poles of said magnets facing outwardly from said housing andbeing directly engageable with the ends of the studs opposite to thestud ends engageable by said armatures aforesaid to thereby establishelectrical engagement with said studs, and to subject the studs tomagnetization by said magnet poles, whereby when the plug element isbrought into position with respect to the socket element to register themagnet poles with the studs magnetic influence is transmitted throughthe studs to draw the armatures into engagement with the studs tothereby complete electrical circuits to the magnets from the electricalterminals aforesaid, and whereby the U -shaped magnets are individuallymovable into contact with the corresponding studs, together withelectrical connections from the magnets to suitable delivery lines.

2. A structure as defined in claim 1, together with means to limit themovement of each magnet with respect to the housing.

WILLIAM McLEOD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,778,481 Boucher Oct. 14, 19301,978,065 Twombly Oct. 23, 1934 2,044,948 Leon June 23, 1936 2,234,982Ross Mar. 18, 1941 2,298,313 Ross Oct. 13, 1942 2,448,832 Ross Sept. 7,1948 2,474,942 Hawkins July 5, 1949 FOREIGN PATENTS Number Country Date865,035 France Feb. 10, 1941

